BKG WCS — bkg_wcs • ffm

Low-level interface to BKG-style web coverage services (WCS). This function is used in all high-level functions of ffm that depend on a WCS, e.g., bkg_dem.

Usage

bkg_wcs(
  coverage_id,
  endpoint = coverage_id,
  version = "2.0.1",
  method = NULL,
  format = "image/tiff;application=geotiff",
  epsg = 3035,
  interpolation = NULL,
  ...
)

Arguments

coverage_id

Coverage ID. When in doubt, inspect the GetCapabilities of the service.

endpoint

Endpoint to interface. Note that wcs_ is appended and only the rest of the product name must be provided. For example, wcs_dgm200_inspire becomes dgm200_inspire. Defaults to the value of coverage_id.

version

Service version of the WCS. Defaults to 2.0.1.

method

HTTP method to use for the request. GET requests provide parameters using URL queries. Filters must be provided as CQL queries. While this is less error-prone, it allows a maximum number of only 2048 characters. Especially when providing more sophisticated spatial queries, GET queries are simply not accepted by the services. In these cases it makes sense to use POST requests instead.

If NULL, the method is inferred from the type of filter query provided to filter (either XML or CQL). If no filter is provided, the method is inferred from getOption("ffm_query_language").

format

Content type of the output. This value heavily depends the endpoint queried. Defaults to "image/tiff;application=geotiff".

epsg

Numeric value giving the EPSG identifier of the coordinate reference system (CRS). The EPSG code is automatically formatted in a OGC-compliant manner. Note that not all EPSG codes are supported. Inspect the GetCapabilities of the target service to find out which EPSG codes are available. Defaults to EPSG:3035.

interpolation

Method used to interpolate the coverage raster. Allowed methods depend on the capabilities of the WCS.

...

Further parameters passed to the WFS query. In case of POST requests, additional namespaces that may be necessary to query the WFS. Argument names are interpreted as the prefix (e.g. xmlns:wfs) and argument values as namespace links.

Value

A SpatRaster.

Examples

if (FALSE) { # getFromNamespace("ffm_run_examples", ns = "ffm")()
# Boundaries can be provided using two subset arguments
bkg_wcs(
  "dgm200_inspire__EL.GridCoverage",
  endpoint = "dgm200_inspire",
  subset = "E(548282,552280)",
  subset = "N(5800943,5804942)"
)
}